RUSSIAN Russian wheat aphid (Diuraphis noxia) is a new to Australia, first detected in cereal crops in South Australia in May 2016.

While grain growers are used to dealing with and USE THE GRDC FITE STRATEGY other endemic pests of production, Russian wheat aphid is new to Australia. Overseas, the aphid has caused huge 1. FIND – look for aphids and the losses if untreated, but it is not yet known what effect characteristic plant symptoms of leaf it will have here. streaking or leaf rolling on cereal crops and grasses HOW RUSSIAN WHEAT APHID DAMAGES CROPS 2. IDENTIFY – positively identify the Russian wheat aphid can cause direct yield losses and pest in consultation with a specialist damage, unlike other aphids which are a problem because they transmit viruses. 3. THRESHOLD APPROACH – consider Yield impacts depend on the crop development stage. international thresholds for control, Aphids feeding during the early booting to soft dough stage factoring crop growth stage and can cause direct yield losses. After soft dough stage, potential yield losses it appears that further impact is minimal. 4. ENACT an appropriate management If aphids are controlled plants may recover unless strategy that where possible excessively stressed. Overseas data suggests that this preserves beneficial . aphid does not thrive in conditions above 25oC, but this needs to be confirmed in Australian conditions.

WHERE IS IT NOW? The latest distribution maps can be found at http://bit.ly/RWAdist

IF YOU SEE ANYTHING UNUSUAL, CALL THE EXOTIC PLANT PEST HOTLINE 1800 084 881

PHA-16-037 FITE 1. Find

Growers and agronomists are urged to HOW TO FIND THE APHID check cereal crops and grass weeds for aphids and damage symptoms. Search strategies for Russian wheat aphid vary with the density of infestation, weather conditions, and crop Report suspect detections outside the current known development stage. Once seedlings emerge, check crops distribution to the Exotic Plant Pest Hotline or directly regularly. to each state. Russian wheat aphid feeds in dense colonies, typically at the base and sheath of younger leaves and within leaves curled by their feeding. IF YOU SEE ANYTHING UNUSUAL, In lower densities, it is much easier to detect characteristic CALL THE EXOTIC PLANT PEST HOTLINE leaf streaking and rolling in plants rather than find aphids. In good weather conditions, the aphids prefer the newest 1800 084 881 leaves of plants, and are often found on the last two leaves unfurled. In poor conditions, the aphids will usually be found Russian wheat aphid may infest crops during any stage sheltering within leaf curls. Heavy rain has been found to of crop development, from early establishment to flag leaf reduce populations by up to 50%. At high densities they development. Russian wheat aphid symptoms can become can be found on any leaf parts. apparent quickly, with even a few aphids causing visible Overseas Russian wheat aphid tends to move into crops symptoms as early as 7 days after infestation. in Autumn, shelter inside leaf rolls over winter remaining Damage is characterised by: at low levels and then multiply quickly in Spring. The main aphid flights occur in Spring. • Longitudinal rolling of leaves, forming a hollow tube inside which aphids shelter. As with other aphids, infestations often begin along crop edges, usually on the windward side or adjacent • Whitish, yellowish to pink-purple chlorotic streaks to infested grasses. Be sure to check areas of paddocks along the length of leaves. where plants are sparse or adjacent to bare ground. • Stunted plants which may appear flattened, with After initial infestation, aphids can rapidly spread across tillers lying almost parallel to the ground. a paddock. • Viewed from a distance, damage may appear as a general loss of colouration across the affected crop area. • In older crops, wheat awns may become trapped in the boot, resulting in hook-shaped head growth and bleaching, and reduced yield. Russian wheat aphid

How to recognise it Russian wheat aphid Adult oat aphid

Russian wheat aphid (Diuraphis noxia) is now in parts of South Australia, Victoria, and New South Wales. Hosts FITE 2. Identify • Wheat, , oats, rye and triticale. • Many other grass species, including weeds. è è What to look for Positively identify Russian wheat aphid in

• Plant symptoms together with the presence of aphids. consultationDouble tail (arrows) andwith a specialist.Has siphuncles (circled) and • White, yellowish and purple/red streaks along leaves. no siphuncles (circled) no double tail • Leaf rolling along margins • Awns trapped by rolled flag leaf. HOW TO RECOGNISE RUSSIAN • Heads can have a bleached appearance. WHEAT APHID Russian wheat aphid may be present in mixed populations. If aphids which are commonly found in cereals are observed it should not be assumed these The pest is small and pale green in colour are the only ones present. often with a fine coating of whitish wax. What does the aphid look like? Compared to other grain aphids, it is • Elongated body up to 2 mm in length. elongated in shape. • Pale yellowish-green to grey-green in colour. • Double tail, no siphuncles. See comparison images. Wingless (apterous) adults have very short antennae, about a third to half Damage from Russian wheat aphid What to do if you suspect Russian wheat Albert Gorman the body length, and have no obvious aphid? siphunculi (‘exhaust pipes’). A key management strategy for RWA overseas is to preserve populations of predators and other beneficials The winged (alate) adults are small, to help control aphid numbers. This strategy should be used in Australia wherever possible. up to 2 mm in length, with body-length RWA is likely to warrant chemical control if infestations antennae. They are generally darker exceed thresholds of 10% of plants infested through the green compared with the wingless adults. high risk period of early booting to soft dough (Z40 – Z85). In crops where RWA has been identified, the easiest They have two short ‘tails’ (caudal) way to determine a 10% level of damage is to assess RussianRussian wheatwheat aphidaphidprocesses) on the end of the abdomen if at least 5 tillers from a total of 50 tillers are showing one above the other, giving the symptoms of aphid damage (see above under “what to Russian wheat aphid colony. Note leaf rolling and streaks look for”) and aphids. along the leaf appearance of a double tail. Albert Go It is important that representative parts of the paddock Streaks along the leaf Albert Gorman are assessed before determining if the threshold has HowHow toto recogniserecognise itit RussianRussian wheat aphid Adult oatoat aphidaphid been reached. HOST RANGE: Contact your state department of agriculture or RussianRussian wheat wheat aphid aphid ( Diuraphis(Diuraphis noxia noxia) )is is nownow inin partsparts your agronomist for advice on controlling this pest. Russian ofwheatof South South aphid Australia, Australia, affects Victoria, Victoria, more and andthan New New 140 South South species Wales.Wales. of cultivated and wild grasses. These include wheat, barley, triticale, Hostsrye,Hosts oats, pasture grasses and weeds including brome grass,•• Wheat,Wheat, barley barley, barley, grass, oats, oats, ryegrass rye rye and and and triticale. triticale. phalaris. •• ManyMany other other grass grass species, species, including including weeds.weeds. èè èè August 2016 Wheat and barley are most susceptible; triticale, rye and oatsWhat lessWhat so. to to look look for for

•• PlantPlant symptoms symptoms together together with with the the presence presence ofof aphids.aphids. DoubleDouble tail (arrows) and Has siphuncles (circled)(circled) andand •• White,White, yellowish yellowish and and purple/red purple/red streaks streaks alongalong leaves.leaves. nono siphunclessiphuncles (circled) no double tailtail Bugwood.org Bugwood.org SARDI SARDI •• LeafLeaf rolling rolling along along margins margins •• AwnsAwns trapped trapped by by rolled rolled flag flag leaf. leaf. •• HeadsHeads can can have have a a bleached bleached appearance. appearance. RussianRussian wheat wheat aphid aphid may may be be present present in in mixedmixed populations.populations. If If aphids aphids which which are are commonly commonly foundfound inin cerealscereals are are observed observed it it should should not not be be assumed assumed thesethese areare the the only only ones ones present. present.

WhatWhat does does the the aphid aphid look look like?like? •• ElongatedElongated body body up up to to 2 2 mm mm in in length. length. •• PalePale yellowish-green yellowish-green to to grey-green grey-green in in colour.colour. •• DoubleDouble tail, tail, no no siphuncles. siphuncles. See See comparison comparison images.images.

DamageDamage from Russian wheat aphid WhatWhat to to do do if if you you suspect suspect RussianRussian wheatwheat Albert Gorman Albert Gorman aphid?aphid? AA key key management management strategy strategy for for RWA RWA overseas overseas isis toto preservepreserve populations populations of of predators predators and and other other beneficialsbeneficials toto help help control control aphid aphid numbers. numbers. This This strategy strategy shouldshould bebe usedused in in Australia Australia wherever wherever possible. possible. RWARWA is is likely likely to to warrant warrant chemical chemical control control if if infestationsinfestations exceedexceed thresholds thresholds of of 10% 10% of of plants plants infested infested throughthrough thethe highhigh risk risk period period of of early early booting booting to to soft soft dough dough (Z40(Z40 –– Z85).Z85). InIn crops crops where where RWA RWA has has been been identified, identified, thethe easiesteasiest wayway to to determine determine a a 10% 10% level level of of damage damage isis toto assessassess if ifat at least least 5 5 tillers tillers from from a a total total of of 50 50 tillers tillers areare showingshowing symptomssymptoms of of aphid aphid damage damage (see (see above above underunder “what“what toto RussianRussian wheat aphid colony. Note leaf rolling andand streaksstreaks looklook for”) for”) and and aphids. aphids. alongalong thethe leaf Albert Gorman Albert Gorman It Itis is important important that that representative representative parts parts of of thethe paddockpaddock areare assessed assessed before before determining determining if if the the threshold threshold hashas beenbeen reached. reached. ContactContact your your state state department department of of agriculture agriculture oror youryour agronomist agronomist for for advice advice on on controlling controlling thisthis pest.pest.

AugustAugust 2016 2016 FITE 3. Threshold approach

In grain growing regions overseas a key HOW TO CHECK FOR 10% DAMAGE management strategy for Russian wheat Check several parts of the paddock to assess infestation. aphid is to preserve populations of Five tillers from a total of 50 are showing symptoms (leaf predators and other beneficials to help rolling, white or red streaking, head caught in the boot) control aphid numbers. This strategy should or Russian wheat aphid is present. be used in Australia wherever possible. It is important to note that the decision to spray must be based on individual situations and broader consideration of This means that where the aphid has been confirmed, factors including crop yield potential, timing of infestation, growers need to estimate infestation levels regularly, number of aphids per tiller and the cost of the chosen particularly as temperatures start to rise in Spring. control option. Based on data from overseas, Russian wheat aphid is likely to warrant chemical control if levels are above thresholds of 10% of tillers infested through the high risk period of early booting to soft dough (Z40 - Z85). During this period, protecting the top three leaves will be a priority for minimising yield loss.

Economic thresholds recommended to guide spraying are: • 20% plants infested up to the start of tillering • 10% of tillers infested after tillering

This advice may change once information from Australian trials is completed. Aphid colony Frank Peairs, Colorado State University, Bugwood.org Frank Peairs, Colorado State University,

RESEARCH IS UNDERWAY

Research to learn more about the aphid and how to manage it under Australian conditions is underway. GRDC is working on identifying the biotype of the pest, effective chemical control options, yield loss and thresholds for control, resistant varieties of grain crops, the biology and population dynamics of the aphid and the importance of natural enemies. FITE 4. Enact

Growers need to choose an appropriate management strategy based on thresholds, preserving beneficial insects wherever possible. Insecticides can kill foraging bees. It is essential that you contact beekeepers CHEMICAL CONTROL before spraying if you have hives on or near your property. See beeaware.org.au If chemical control is warranted, use pirimicarb which for more information. is softer (less toxic) on many beneficial species. Pirimicarb is listed for control under Emergency Use Permit (APVMA82792). Follow label directions and consider using BENEFICIAL INSECTS lower rates at higher temperatures. Note: pirimicarb has a witholding period of 42 days for grazing and harvest. Many growers overseas make use of natural enemies of Russian wheat aphid to control the pest. Chlorpyrifos is also listed under this Emergency Use Permit at a rate of 600 ml/ha. This rate been shown to be effective Predators in Australia include: in killing the aphid, but it also harmful to beneficials. • parasitoid wasps Note that killing the natural predators could cause a • generalist predators including lady beetles subsequent spike in numbers of other aphid species or allow any remaining Russian wheat aphids to multiply • lacewings rapidly. • damsel bugs Good spray coverage is essential to optimize the • hoverflies effectiveness of insecticide spray treatments, particularly • some fungi where aphids are sheltered in rolled leaves. RECOMMENDED PROCEDURE: water volumes of at least 100 L/ha, the inclusion of a non-ionic surfactant and nozzle IF YOU SEE ANYTHING UNUSUAL, pressures that deliver mid-size droplets. CALL THE EXOTIC PLANT PEST HOTLINE When considering seed treatment for the 2017 season please note that imidacloprid is listed for control under Emergency Use Permit (APVMA PER8304) at a rate of 1800 084 881 120ml/100kg of seed. Follow label directions.

For more information speak to your Grains Biosecurity Officer:

STATE GRAINS BIOSECURITY OFFICER PHONE EMAIL NSW Bill Gordon 0428 133 944 [email protected] QLD Kym McIntyre 0429 727 690 [email protected] SA Judy Bellati 0412 218 228 [email protected] VIC Jim Moran 0418 377 930 [email protected] WA Jeff Russell 0447 851 801 [email protected]

For more information on Russian wheat aphid visit http://bit.ly/RWAmanage